Quote from futurecurrents:
To explain the chart.......
Dr Shakun's team has now constructed a narrative to explain both what was happening on Antarctica and what was happening globally:
This starts with a subtle change in the Earth's orbit around the Sun known as a Milankovitch "wobble", which increases the amount of light reaching northern latitudes and triggers the collapse of the hemisphere's great ice sheets
This in turn produces vast amounts of fresh water that enter the North Atlantic to upset ocean circulation
Heat at the equator that would normally be distributed northwards then backs up, raising temperatures in the Southern Hemisphere
This initiates further changes to atmospheric and ocean circulation, resulting in the Southern Ocean releasing CO2 from its waters
The rise in CO2 sets in train a global rise in temperature that pulls the whole Earth out of its glaciated state
Prof Eric Wolff from the British Antarctic Survey was the chief scientist on the longest Antarctic ice core, which was drilled at Dome Concordia in 2001/2002. This core records eight ice ages, not just the most recent, stretching back some 800,000 years.
He was not involved in the Nature study. Prof Wolff told this week's Science In Action programme on the BBC World Service:
"It looks as though whatever kicked off this whole sequence of events to get out of the ice age was something really, in global terms, rather minor and regional, and yet it led to a sequence of events that led to a complete change in the way the surface of the Earth looked, with ice sheets disappearing.
"So, that just reminds us that although climate might seem quite steady to us because it's been relatively steady for the last few thousand years, it is actually capable of undergoing big changes. And as one famous palaeoclimatologist put it: 'we poke it at our peril'."